Blackberry plant named &#39;Chesapeake&#39;

ABSTRACT

The present invention is a new and distinct thorny blackberry cultivar named ‘Chesapeake’, which is capable of producing very large fruit in the spring midseason, the fruit being much larger and similarly durable than that of the standard cultivars. The cultivar is characterized by moderate suckering ability, recurved thorns and its very flavorful fruit which is edible even when the fruit is immature.

FIELD OF THE INVENTION

[0001] This invention concerns a new and distinct cultivar of thornyblackberry plant with a botanical name of Rubus argutus×R. cuneifoliusL.

DESCRIPTION OF RELATED PRIOR ART

[0002] Several cultivars of thorny blackberry plants are known.‘Chesapeake’ may be distinguished from its parent, ‘Shawnee’ (U.S. PlantPat. No. 5,686) and other large fruited thorny blackberry cultivars suchas ‘Kiowa’ (U.S. Plant Pat. No. 9,861) by the recurvature of its spinesand flavor of its fruit. It may be distinguished from ‘Black Butte’(unpatented) by the type of spines and its erectness, compared to thesemi trailing habit of the large fruited ‘Black Butte’. Fruit size andflavor distinguishes ‘Chesapeake’ from all other thorny blackberrycultivars known to us, including ‘Choctaw’ (U.S. Plant Pat. No. 6,678),‘Illini Hardy’ (U.S. Plant Pat. No. 8,333), ‘Raven’ (unpatented) and‘Ranger’ (unpatented). The presence of thorns and the size of the fruitdistinguish ‘Chesapeake’ from thornless cultivars such as ‘Arapaho’(U.S. Plant Pat. No. 8,510), ‘Navaho’ (U.S. Plant Pat. No. 6,679), ‘HullThornless’ (unpatented), ‘Triple Crown’ (unpatented) and ‘ChesterThornless (unpatented).

ORIGIN OF THE NEW CULTIVAR

[0003] The new cultivar of blackberry originated from a controlled crossat the University of Maryland Greenhouses in College Park, Md. The cross“SKNA” was ‘Shawnee’ (U.S. Plant Pat. No. 5,686)×R. cuneifolius (a wildselection from the town of Crisfield, Md.) and was made in the winter of1993 as part of the Ph.D. thesis research of Dr. Sara Kristine Naess.This year was designated “N” as part of the University of Maryland atCollege Park; Rutgers University of New Brunswick, N.J.; VirginiaPolytechnic Institute and State University, Southern PiedmontAgricultural Research and Education Center at Blackstone; and theUniversity of Wisconsin at River Falls cooperative breeding program. Theclone was first selected in 1992 at the Wye Research and EducationCenter of the University of Maryland located at Centerville, Md. and wastherefore designated “−1”. Thus, the complete breeding designation was“NSKNA-1”.

SUMMARY OF THE NEW CULTIVAR

[0004] This application relates to a new and distinct thorny, Springbearing blackberry cultivar, botanically known as Rubus argutus×R.cuneifolius L. The following characteristics are outstanding:

[0005] 1. Production of fruit which is much larger than the standardcultivars in use and larger or of equal size to two new extra largecultivars, ‘Black Butte’ (unpatented) and ‘Kiowa’ (U.S. Plant Pat. No.9,861).

[0006] 2. Production of fruit which is more flavorful than all otherthorny blackberry cultivars known to us.

[0007] The following characteristics are useful in distinguishing thiscultivar and can be useful for cultivar identification.

[0008] 1. Plants are sparingly suckering and very upright, growing to 12feet or taller when mature. Canes are only moderately cold hardy, i.e.not recommended for areas where the minimum winter temperature is lessthan 0° F.

[0009] 2. Canes, petioles, petiolules and leaf midribs have only amoderate amount of large recurved thorns.

[0010] 3. The fruit is very large, typically 15-22 grams in the firstpicking and has an aroma of a blueberry in cooler temperatures. Theflavor contains undetectable quantities of highly aromatic compoundstypical of eastern U.S. erect thorny or semierect thornless blackberrycultivars.

[0011] 4. The fruit is produced in the midseason from floricanes.Primocane produced fruit is unknown.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

[0012] The accompanying photographs show typical characteristics of thenew variety:

[0013]FIG. 1 shows a young ‘Chesapeake’ plant in July 2000, theprimocane height is 6 feet. The plants are in their second growingseason in Millersville, Pa.

[0014]FIG. 2 shows the type and density of thorns on the apex of afluted ‘Chesapeake’ primocane.

[0015]FIG. 3 shows a ‘Chesapeake’ flowering truss, leaves and themidsection of a ‘Chesapeake’ primocane.

[0016]FIG. 4 shows typical ‘Chesapeake’ flowers.

[0017]FIG. 5 shows a fruiting cluster of ‘Chesapeake’, showing unopenedflowers through fruit 3 weeks post pollination.

[0018]FIG. 6 shows a fruiting cluster of ‘Chesapeake’ from a two yearold plant in Oak Grove, Va.

[0019]FIG. 7 shows several ripe fruit of ‘Chesapeake’.

DESCRIPTION OF THE NEW CULTIVAR

[0020] The following is a detailed description of the new cultivar,together with the cultivar's morphological characteristics. Thecharacteristics of the cultivar were compared other standards used inthe Mid-Atlantic Region of the U.S. and a parent, ‘Shawnee’ (U.S. PlantPat. No. 5,686). The description is based on information provided bycooperating growers and scientists from plants grown in fields at CreamRidge and Colt's Neck, N.J., Millersville, Pa., and Oak Grove, Va., andfrom plants grown in the University of Maryland greenhouses at CollegePark, Md.

[0021] ‘Chesapeake’ produces a moderate number of root- andcrown-suckers, typically 2.7 per plant or 13 per 10 foot of row asmeasured on 3 year old plants in Colt's Neck, N.J., similar to ‘Shawnee’(U.S. Plant Pat. No. 5,686) and other thorny blackberry cultivars testedor grown in the eastern United States. It can therefore be trained as ahedgerow or maintained as individual plants. During the growing season,primocanes are light green colored (Royal Horticultural Society plate143B vs. 146B for ‘Shawnee’) with a light red blush (Royal HorticulturalSociety plate 59A) in full sun, fluted or moderately grooved, usuallybranched, very erect with arching branches and very vigorous (see FIG.1). Floricanes are not noticably exfoliating, with only an occasionalnarrow split. Floricane color is brown (Royal Horticultural Societyplate 178A). In the growing season, primocane thorns are moderate indensity, 5 mm in length and 3.5 mm diameter at their base, sometimesrecurved basipetally and light red (Royal Horticultural Society plate59A) at the base, but lighter in color (59B to 59C) and thinner at theirapex (see FIG. 2). The red coloration does not extend into thesurrounding cane. Leaf upper surfaces are dark green, most closely inhue to Royal Horticultural Society Color plate 137A, while the lowersurface of the leaf is pubescent giving this surface a greyer color(Royal Horticultural Society plate 147B) (see FIGS. 2 and 3). Leaves aretrifoliolate to pentafoliolate and average 14 cm from the distal end ofthe petiole to the distal end of the terminal leaflet. The basalleaflets average 14 cm from terminal point to point. The petiole is 5 cmin length and the same light green color as the cane, RoyalHorticultural Society plate 143B. Leaf serration is common for mostcultivars of blackberry and cannot be used to distinguish this cultivar.

[0022] ‘Chesapeake’ floricanes suffer cold injury in mid winter iftemperatures fall below 0° F. Canes can flower from all live buds inApril to May depending on latitude, and fruit from mid June to late Julyin the eastern U.S. This ripeness period is 1-2 weeks later than ‘HullThornless’ (unpatented) and ‘Navaho’ (U.S. Plant Pat. No. 8,510), butoverlaps ‘Chester Thornless’ (unpatented) and ‘Kiowa’ (U.S. Plant Pat.No. 9,861).

[0023] The flower morphology and early fruit morphology is typical ofmost eastern U.S. originated blackberry cultivars (the flowers areunscented, 5 white petals 1 to 2 cm long with color resembling RoyalHorticultural Society plate 155D, with a slight pink shading on theopening flower resembling Royal Horticultural Society Plate 62C; 5sepals, resembling Royal Horticultural Society plate 147B and 3 cm longand which cannot be used to identify ‘Chesapeake’ (see FIG. 4). Flowerpetals abscise within seven days post pollination

[0024] Fruit trusses are typical cymose clusters with 6 to over 15 fruitwell spaced out on a truss axis (see FIGS. 5 and 6). After 25 days afterpollination, fruit is distinguishable for this variety by its size only;at this point, unripe fruit is light green (Royal Horticultural Societyplate 183 C). Fruit is dark black internally and externally when ripe,closely resembling Royal Horticultural Society color plate 202A (seeFIG. 7). Fruit has little pubescence, producing a glossy appearance.Fruit is decidedly thick elongate (commonly up to 4 cm in length and 2cm in width), very large (15-22 gram primary fruit) and somewhatasymmetrical due to variation in drupelet placement (see FIG. 7).Drupelets are held together tightly and the fruit does not “crumble”.Fruit separates when slightly unripe, but does not abscise prematurely.Fruit skin toughness is less than ‘Chester Thornless’ (unpatented), butsimilar to other thorny cultivars such as ‘Shawnee’ (U.S. Plant Pat. No.5,686). The fruit is very “juicy” when crushed and the drupelets arerelatively large. Seed size, including woody endocarp, is large,averaging 4.6 mg per seed fresh weight. Fruit flavor is sweet, even whenthe fruit is unripe. The torus separates from the plant and darkensslightly, from white, upon ripening. The fruit does not break down afterat least one week in common storage at 40° F.; however, some drupeletswill turn dark red upon storage for even a short period of time (<6 hr).This is typical of blackberry fruit grown in warm climates. Flavor issweet even when unripe, and not characteristic of modern easternblackberry cultivars, which tend to be highly acid when unripe and“tar-like” when ripe and warm. When grown in cooler regions, or during acooler than normal spring, ‘Chesapeake’ fruit has an aroma reminiscentof blueberries.

[0025] The plant is field resistant to many of the common pests anddiseases in the eastern United States, e.g. mildew and Phytophthorafragarae root rot and fruit rot, based on field reaction, not incontrolled testing. The plant has not had orange rust or verticilliumwilt in several years of exposure in the field, but no claim ofresistance is made.

[0026] ‘Chesapeake’ has been asexually reproduced by tissue culture andfield suckering since 1994. Over that period, no off-type of‘Chesapeake’ has been observed or reported to us. Tissue cultureexplants originated from lateral bud meristems and multiplication mediumcontained 3 to 10 micromolar benzyl adenine. Plants were propagated atSouth Deerfield, Mass., Hurlock, Md. and the Department of NaturalResource Sciences, University of Maryland, College Park, Md.

What is claimed is:
 1. A new and distinct thorny blackberry plant knownas ‘Chesapeake’ as described herein, illustrated and identified by thecharacteristics set forth above.